title: Environmental enrichment may protect against hippocampal atrophy in the chronic stages of traumatic brain injury.
abstract: OBJECTIVE
  To examine the relationship between environmental enrichment (EE) and hippocampal atrophy in the chronic stages of moderate to severe traumatic brain injury (TBI).
  
  
  METHODS
  Retrospective analysis of prospectively collected data; observational, within-subjects.
  
  
  METHODS
  Patients (N = 25) with moderate to severe TBI.
  
  
  METHODS
  Primary predictors: (1) An aggregate of self-report rating of EE (comprising hours of cognitive, physical, and social activities) at 5 months post-injury; (2) pre-injury years of education as a proxy for pre-morbid EE (or cognitive reserve).
  
  
  METHODS
  bilateral hippocampal volume change from 5 to 28 months post-injury.
  
  
  RESULTS
  As predicted, self-reported EE was significantly negatively correlated with bilateral hippocampal atrophy (p < 0.05), with greater EE associated with less atrophy from 5 to 28 months. Contrary to prediction, years of education (a proxy for cognitive reserve) was not significantly associated with atrophy.
  
  
  CONCLUSIONS
  Post-injury EE may serve as a buffer against hippocampal atrophy in the chronic stages of moderate-severe TBI. Clinical application of EE should be considered for optimal maintenance of neurological functioning in the chronic stages of moderate-severe TBI.
authors.affiliation: Applied Psychology and Human Development, Ontario Institute for Studies in Education, University of Toronto Toronto, ON, Canada.
authors.forename: Lesley S
authors.initials: LS
authors.lastname: Miller
authors.forename: Brenda
authors.initials: B
authors.lastname: Colella
authors.forename: David
authors.initials: D
authors.lastname: Mikulis
authors.forename: Jerome
authors.initials: J
authors.lastname: Maller
authors.forename: Robin E A
authors.initials: RE
authors.lastname: Green
keywords: adult; environmental enrichment; moderate to severe; subacute atrophy; traumatic brain injury